Device for trimming lawns



, May 4, 1943. w. J. ROWAN 2,318,334

DEVICE FOR TRIMMING LAWNS Filed'Nov. 13, 1940 A Trek/w56.

Patented May 4, 1943 2,318,334 DEVICE FOR TRIMMING LAWNS William J. Rowan, Los Angeles, Calif.

Application November 13, 1940, Serial No. 365,432

20 Claims. (Cl. 56-249) My invention relates to 'a lawn-trimming device and, morev particularly, to a device for trimming the grass in an annular zone around sprinkler heads, golf-green cups, etc. The invention .will be particularlyl described with reference to a moving device adapted to facilitate cutting of grass around a sprinkler head, but it will be apparent that other uses are contemplated.

The'usual lawn mower does not trim'the grass accurately around a sprinkler head. Sometimes the sprinkler head is elevated so that the lawn mower cannot be safely run thereacross. More commonly, the sprinkler head is flush or slightly above the top of the ground so as to clear the blades of the lawn mower, but a conventional f This is particularly true with regard to lawns containing Bermuda grassor other growth having a spreading characteristic, and which tends to cover the top of the sprinkler head to interfere with the desired spray. It is conventional practice to hand-clip this grass from above the sprinkler head and, sometimes, the grass in an annular zone therearound.

It is an object of the present invention to provide a simple device for trimming lawns adjacent a sprinkler head and, more particularly, to provide such a device which can be centered with respect to the desired zone to be trimmed, and which provides a mowing means adapted for revolution around the central axis so as to trim the grass in an annular zone.

Another object of the invention is to provide an annular engagement or centering means which' can be inserted in the ground or concentric with a device mounted in the ground, such as a sprinkler head or golf-green cup, and which serves both to establish a center around which the mowing unit can revolve and to cut or displace grass growing at a position adjacent or toward the inside of the engagement means.

Another object of the invention is to provide a mowing unit which can be moved in an annular path and which is operated at a point convenient to the operator.

Still another object of the invention is to provide a mowing unit of the general type described and which is driven by a crank positioned above the unit.

Yet another object of the invention is to provide a mowing device in which the turning of a single element, for example a crank, will both turn the blades of a mowing unit and revolve the mowing unit to mow the grass in an annular zone. f

Anotherobject of the invention is to provide a mowing unit includingmovable and stationary shearing means, such as movable and stationary blades, the shearing action preferably being along a line inclinedvwith respect to the horizontal.

Another object of the invention is to provide such an inclined shearing means in combination with a mowing unit adapted for movement in an annular zone around a predetermined vertical axis so as to cut a swath of frusto-conical shape.V

By way of example, the invention has beenl shown in Figure 1 for use in clipping or mowing grass around a sprinkler head, indicated generally by the numeral I0, this head being shown --as mounted slightly above the surfacel of the ground I I, from which grass I2 is growing.

The invention includes, generallyy a mowing Y device I5 including a body I6 carrying a mowing unit I'I' adapted to encircle the sprinkler head Ill to mow an annular zone of grass therearound. The mowing device I5 is adapted to be actuated by control mechanism, indicated generally by the numeral I8, and usually positioned about three feet above the mowing unit I1. to be convenient to the operator.

More specically, the body I6 includes a centering or ground-engageable pivot means, shown as comprising an engagement means 20. This centering means acts in the nature of a pivot or anchor means and determines the center about which the mowing unit I1 is to be turned to mow a desired annular zone concentric with this center. The engagement means 20 is adapted for engagement with the ground or with some device i mounted therein, for example the sprinkler head I0, the cup of a golf-green, etc., and the terms ground-engageable or ground-anchoring are herein used to cover any such modes of pivotal attachment. Such an engagement means may contact the ground or such other device at a single point or in an annular zone, asr shown in Figure 1.

Preferably, the engagement means provides an annular cutter 22 of tubular shape and of Y sufficient diameter to extend downward close to the periphery of the sprinkler head I0. Lowering this cutter 22 into the position shown in Figure 1 will tend to depress or cut any grass or Weeds growing inward across the top of the sprinkler head. To facilitate the cutting action, the lower end of the cutter 22 is beveled, as indicated by the numeral 23, to provide a relatively sharp cutting edge 24.

It is preferable to make the engagement meansl 20 removable with respect to the body I6. For this purpose, the body provides a depending wall 25 which telescopes with a projection 26 of the cutter 22, one or more screws 21 acting to retain` the cutter in place. A circular plate 28 is clamped in place between the projection 26 of the cutter and an annular wall 29 provided by the body I6. Below this plate, the structure provides a space for receiving a sprinkler head, and the plate separates this space from a gear chamber 30 and edge 34 and a desired number of movable blades 35, each providing shearing edges 36 disposed to shear across the `edge 34 of the stationary blade 33. The blades 33 and 35 should preferably extend inward close to the surface of the body I6 to mow a zone immediately adjacent. The number of blades 35 can be varied from that shown Without departing from the spirit of the invention, and should be sufficient so that the mowing unit will not leave ridges when it is turned through its annular locus of motion around the sprinkler head.

Preferably, the blades 35 extend substantially helically with respect to a shaft 38 to which they are connected, as by brackets 39. In addition, the rotor formed by these elements is not of uniyform size throughout its length but preferably tapers inward toward the shaftV 38 toward the outer end thereof. The blade 33 is then disposed at an angle inclined with respect to the horizontal so that the grass-shearing action takes place on a slight incline. The blade 33 may be inclined only a few degrees from the horizontal, an inclination of from 5 to 10 being found very desirable. On the other hand, it is within the contemplation of the invention that the blade 33 may be horizontal and the rotor not tapered if the annular zone to be mowed is 'to be at rather than frusto-conical.

The shaft 36 of the mowing unit is preferably pivoted both in the body I6 and in a position spaced therefrom. Serving the latter purpose are upper and lower arms 40 and 4I providing bent and mutually-overlapping portions 46' and 4I held together as by rivets 42. These portions 48' and 4I may be drilled to journal the shaft 38 or suitable anti-friction bearings can be used at this point to journal the shaft. The upper arm 40 is preferably connected to the body I6. As shown in Figure l, this can be accomplished by bending the arm 40- out of its normal plane to form a tab 44 shaped to conform to the periphery of the body I6 and secured thereto, as by,screws 45. The lower arm 4I may be similarly or otherwise secured to the body I6 and the blade 33 is preferably removably attached thereto by any sultable means.

The shaft 38 is shown as being journalled in horizontally-aligned openings 46 and 41V of the body I6, though suitable anti-friction bearings can be incorporated at this point, if desired. A

collar 48 within the gear chamber 30 serves to prevent outward movement of the shaft 38 and inward movement of this shaft toward the body is prevented by a collar 49, these collars resting adjacent opposite side walls of the gear chamber 30.

Gear means is provided within the gear chamber 30 for turning the shaft 38 and the blades 35. with respect to the blade 33. This gear means preferably includes a beveled gear 50, which may well be formed integrally with the collar 49, and Ya beveled gear 5I. The gear 5I is rigidly cony nected to a vertical drive shaft 52 journalled in and extending through Y an opening 53 of the body, this shaft being of such length as to extend upward to the control mechanism I8 to be hereinafter described. Turning of the shaft 52 will thus turn the blades 35 of the mowing unit.

In the preferred embodiment of the invention, mechanism is provided for revolving the mowing unit I1 bodily around a vertical axis coaxial with the engagement means 20 and substantially coaxial with respect to the sprinkler head Il). In

the embodiment shown in Figure 1, this is acber 54.

complished by the same turning of the shaft 52 as is used to drive the blades 35. While various gear systems can be used in this connection, Figure 1 shows an embodiment which has been found particularly effective and extremely simple.

In this connection, the entire body I6 is vmade rotatable with respect to a stationary member 54. This is accomplished by enlarging the upper end of the body I6 to form an upright flange 55 which telescopes with a depending flange 56 of a plate 51 forming the main part of the stationary mem- The inner diameter of the depending ange 56 is only slightly larger than the external diameter of the upright flange so as to obtain a'v desirable journalling effect. To prevent the plate 51 and its ange 56 from being lifted from the body I6, I provide an annular ring 58 secured by screws 59 to the lower edge of the flange 56 and extending inward just below the upright flange 55. Correspondingly, the body I6 is rotatably mounted with respect tothe stationary member 54 and the plate 51 and is prevented from e axial movement with respect` thereto by being v'rotatable between the plate and the attached ring 58.

The body I6 and the plate 51 cooperate in defining a gear chamber 60 through which the shaft 52 extends. Rigidly connected to this shaft in the gear chamber is a small pinion 62 meshing with an idler pinion 63 rotatably mounted on a pin 64, threaded or otherwise secured to the plate 51. This pin 64 provides a head 65 tting into a corresponding cavity of the pinion 63 so that this pinion is normally removable as a unit with the plate 51. 'Ihe pinion 63 meshes with an internally-toothed ring gear 66, as best shown in Figures 1 and 2, this ring gear being suitably secured to the body I6 within the gear chamber 60,

as by one or more screws 61.

The plate 51 is normally stationary during operation of 'this embodiment of the invention. Rotation of the shaft 52 with respect to this plate will thus turn the pinion 62 and transmit force through the idler pinion 53 to the ring gear 66 to turn same about the axis of the shaft 52. As this ring gear is connected tothe body I6, it follows that the body and its attached mowing unit I1 will move about the axis of the shaft 52. The rate of turning of the body Will'be considerably less than the rate of turning of the'shaft 38 as the gear ratio of the gear system comprising gears 62, 63, and 65 is considerably less than the gear ratio of the gear means including the beveled gears 50 and 5|. The rate of turning of the body is so correlated with respect to the rate of turning oi' the blades 35 that the mowing unit will cut smoothly through an annular zone without leaving ridges.

To retain the plate 51 stationary and to interconnect the mowing device I5 and the control mechanism I8, I provide an upright member Ashown as comprising a tube which may be welded or otherwise securedl to the top of ther plate51 and through which the shaft 52 extends. To the upper end of this tube 10 is rigidly connected a lower portion 1I of a handle 12. This lower portion 1I provides vertically-aligned openings 13 and 14 for journalling the upper end of the shaft 52, and a beveled gear 15 is positioned therebetween and rigidly connected to the shaft 52. This beveled gear 15 is disposed in a socket of the lower portion 1I so as to extend outward from the socket to mesh with a larger beveled gear 11 xed rigidlyto a crank 18. The beveled gear 11 and crank y1li are suitably journalled on a shaft 19 mounted'in an opening 80. It will be apparent that the handle 12 serves to retain stationary the plate 51 and at the same time to raise and lower the mowing device I5. I

The invention thus far described is operated as follows. The operator places the engagement means 20 around a sprinkler head I0 and lowers it so that the' annular cutting edge 24 shears the grass growing over the top of this sprinkler head. The handle 12 is then held in a fixed position or raised very slightly, permitting the engagement means 20 to ,be rotatable either by contact with the sprinkler head or by being positioned in the annular groove previously cut by the lowering of the annular cutting edge 24. At this time, the operator turns the crank 18, thus rotating the shaft 52 with respect to the tube 10. As previously f' dcscribedthe blades will turn relatively fast and the body I6 will revolve relatively slowly about the vertical axis of the engagement means. The result will bethat an annular zone is mowed around the sprinkler head. It is usually suilicient to turn the crank 18 until the mowing unit I1 has made onecomplete revolution, but this operation can be repeated. For example, it is possible to center the engagement means 20 with respect to the sprinkler head and slowly lower the entire unit while turning the crank 18 so that the mowing unit I1 moves around the head a plurality of times, each time taking a deeper c ut. It is possible to mow annular zones of varying width by controlling the vertica1 position of the mowing device I5. If the device is lowered only suihciently so that an inner portion of the blade 33 is effective in mowing, it will be apparent that the width of the a'inular zone will be less than if the mowing device I5 is lowered so that the complete length of the blade 33 is effective in the cutting operation. Should it be desired in exceptiona1 instances to trim an annular zone which is of greater width on one side thanon the other, it is only necessaryfor the operator embodiment, the

to hold the unit in suon a position that the tube 10 is slightly inclined from its normal vertical position.

If the operator desires that the mowingfunit I1 should not revolve around the vertical axis of the engagement means 20 when the crank 18V is turned, the device canI be modified so that this turning of the mowing unit will take place only when the handle 12 is turned through a corresponding angle. In other words, the mowing unit can be made non-revolvable with respect to the sprinkler head by rigidly connecting the tube 10 to the body I6. In the embodiment shown in Figure 1, this can be accomplished by removing the plate 51 and detaching the idler gear 63 and the pin 64. Thereafter, the device can be reassembled and a bolt caribe threaded downward into the opening previously receivingthe pin 64, the-bolt being of such length as to-traverse the gear chamber 60 and extend into a depression 82 of the body ls, thus looking the plate 5,1 tothe body and, correspondingly, vpreventing rotation between the tube 'I0 and this-body.

A simplified embodiment of the -invention eliminatingthe gears 62, 63, and 66 is shown in Figure 3. The control mechanism I 8 can be identical with that shown in Figure 1 but, in this embodiment, the body 5,1, is used. y Instead, the lower end of the tube 10 is welded or otherwise secured directlyto the top of the body i6. The gear connections to the mowing unit I1 and the construction of this moving unit will be as shown in Figure 1. -In this means for rotating the mowing unit about the vertical axis of the engagement means 20 or the handle 12, and the operator can walk around the sprinkler head to revolve the mowing unit completely therearound.

Various changes and modifications can be made without departing from the spirit of the ving means substantially invention as dened in the appended claims.

I claim as my invention: f

1. In a device for mowing grass in an annular zone. the combination of: anvupright member providing a longitudinal axis; viding a ground-engageable centering means; means for connecting said body to the lower end of said upright member to dispose said centercoaxial with respect to said longltudinal axis; a stationary blade; means for mounting said stationary blade to extend sidewise from said body at an acute angle with respect to said longitudinal axis; a rotary blade means; means for mounting said rotary/ blade means to turn about an axis above said stationary blade in shearing relationship therewith;

and means for rotating said rotary blade means relative to said stationary blade.

2. In a mowing device, the combination of a body providing a gear chamber; an annular engagement means extending downward from said body and providing a space for the reception of a sprinkler head; a wall separating said space and said gear chamber; a shaft journalled in said body and extending outward therefrom; one or more blades secured to said shaft outside said body; a stationary blade extending outward from said body below said shaft and across which said one or more blades move in shearing relationship; a drive shaft Aextending from a position within said gear chamber to a position above .said body; and gear means in said gear chamber for I 5' does not provide a gear chamber and no separate plate, such as the plate sprinkler head I Il will be the a body pro-t 4 operatively connecting said drive shaft and said outward-extending shaft.

3. In a device for mowing grass in an annular zone, the combination of: .a body including a ground-anchoring engagement means forming a pivot means about which said body can turn;

a mowing unit mounted on said body to extend sidewise therefrom, said mowing unitv including movable and stationary shearing means; and means for moving said movable shearing means ,l across said stationary shearing means.

external surface; `a cutting blade extending outward from a position contiguous to said external surface to a position spaced from said surface; a rotatable shearing means above said blade in shearing relationship therewith, said rotatable shearing means extending outward alongv said cutting blade from a position immediately adjacent said external surface; and means for rotating said shearing means with respect to said blade.

5. In a device for mowing grass in an annular zone, the combination of: a body providing a vertical axis; a mowing unit mounted on said body to extend sidewise therefrom and including movable and stationary shearing means; a drive shaft; gearl means operatively connecting said drive shaft to said movable shearing means to move lsame across said stationary shearing means; and gear means operatively connecting said drive shaft and said body to turn said body and revolve said mowing unit around said axis of said body to mow said annular zone.

6. A combination as defined -inclaim 5, in

which said drive shaft extends vertically from.

said body and including means above said body for turning said drive shaft.

7. In a, mowing device, the combination of: a stationary member providing a vertical axis; a body; means for rotatably attaching said body to said'stationary member to turn about said vertical axis; a mowing unit attached to and extending sidewise from said body and including movable and stationary shearing means, said movable shearing means including a shaft and one or more blades secured thereto, said body including means for journalling said shaft; a vertically-disposed drive shaft; gear means for operatively connecting said shaft of said movable shearing means and said drive shaft; and a second gear means operatively connecting said drive shaft and said body to turn said body about said vertical axis and thus revolve said mowing unit about said'axls.

8. A combination ,as defined in claim '7, in which said second gear means includes a pinion on said drive shaft, an idler gear meshing therewith, means attached to said stationary member for journalling said idler gear, and a ring gear secured to said body and meshing with said idler 9. In a mowing device, the combination of: a body; means for mounting said body for rotation about a vertical axis; a shaft journalled in said body and extending outward from one side thereof; a stationary blade extending outward from said body below said shaft and forminga part of a mowing unit; one or more movable blades carried by said shaft in a position to shear across said stationary blade'and forming a part of said mowing unit; an arm means extending voutward from said body at a position above said which said means for turning said shaft includes a dri've shaft extending upward from said body, a crank disposed above said. body,and a gear means operatively connecting said crank to said drive shaft.

12. `A combination as defined in claim 9, in

which'said means for rotating said body about said axis includes a tube secured to said body and a handle at the upper end of said tube, and in which said means for driving said shaft includes a drive shaft extending upward from said body inside said tube, a rotatable crank adjacent said handle, and gear means connecting said rotatable crank to said drive shaft.

13. In a device for mowing grass in an annular zone, the combination of: a grass-mowing unit including rotatable and stationary shearing means; ground-engageable pivot means exclusively at one end of said mowing unit for anchoring said mowing unit to turn about a vertical axis determined by said pivot means; an upright member extending upward from said pivot means; crank means near the upper end of said upright member; and means for operatively connecting said crank means and said rotatable shearing means to rotate the latter with respect to said stationary shearing means.

14. A combination as defined in claim 1, in which said rotary blade means includes a plurality of blades disposed about said axis which is above said stationary blade, said plurality of blades providing shearing edges lying in a frustoconical section generated about said axis, and in which this axis is substantially perpendicular to said longitudinal axis. l

15. A combination as defined in claim 3, in which said ground-anchoring engagement means comprises an annular member depending from said body to a position below the lowermost portion of said shearing means, and in which said annular member provides a space opening downward and of such size as to receive a sprinkler head.

16. In a mowing device, the combination of: a stationary member providing an axis; a body; means for rotatably attaching said body to said stationary member to turn about said axis; a mowing unit attached to said body and extending sidewise therefrom, said mowing unitl including movable and stationary shearing means; a drive means; and means for simultaneously moving said movable shearing means in shearing relationship with respect to said stationary shearing means and for revolving said mowing unit' and i'or revolving said mowing unit about said vertical axis, said drive means including a. drive shaft, gear means operatively connecting said drive shaft to said body and gear means operatively connecting said drive shaft to said movable shearing means.

18. A combination as dened in claim 3, including a tube `extending upward from said body and a handle connected to the top of said tube,

and in which said means for moving said movable shearing means across said stationary shearing means includes a drive shaft within said tube and means for operatively connecting said drive shaft to said movable shearing means.

19. A combination as dened in claim 3. including a shaft journalled in said body and extending outward. from one side thereof, said movable shearing means including one" or more movable blades carried by said shaft, a lower arm means secured to said body and extending outward below saidshaft and providing end means extending upward to Journal the end of said shaft, said arm means carrying said stationary shearing means. s

20. A combination as deiined in claim 3. in which said stationary shearing means includes a xed blade, and in which said movable shearing means includes a shaft journalled in said body and a plurality of blades'connected thereto to move across said ilxed blade in shearing relationship, and including means for turning said body about said pivot means.

WILLIAM J. ROWAN. 

